1. Field of the Invention
The present invention relates to an image processing device and an image processing program for rapidly processing image data and rendering advanced gradations.
2. Description of Related Art
In recent years, color printers of the type that eject multiple colors of ink from the print head, commonly known as inkjet printers, have become widely popularized as a computer output device. These inkjet printers are widely used to print images that have been processed by a computer or the like in multiple colors and multiple gradations. The color printer renders gradations according to a halftone process that distributes dots according to inputted gradation data.
One method of this halftone process is the error diffusion method. Currently, the error diffusion method is the method most commonly used to reproduce high quality images. To describe the process more specifically, the differences between input values and output values generated for neighboring pixels are stored as error values. The saved error values are collected using a distribution matrix. The collected values are used as feedback for the inputted density of unprocessed pixels. By performing such a feedback process with these error values, it is possible to improve the reproduction of density level on a macro scale.
In addition to the error diffusion method, the dithering method is another halftone processing method that is frequently used. The dithering method determines an output level after comparing input values one-on-one with preset threshold values in a threshold matrix, achieving quick dot output without generating recurrent patterns common to the error diffusion method.